Present techniques of determining key parameters of an FM receiver under test, e.g., receiver sensitivity, bandpass characteristics, and receiving frequency, utilize a large signal generator used in conjunction with an oscilloscope and power meter. While such equipment is suitable for manual operation, it is not adaptable to automatic testing techniques. Signal generators which are adaptable to automated testing techniques, i.e., can be computer controlled, are both complex and expensive. In many cases these equipments have capabilities which are far beyond automated testing requirements, resulting consequently in the associated high cost of over design.